Sometimes the level of engineering in F1 is best described by the smaller simpler parts, an example of this is the humble suspension mounting. This part being the point where the wishbone meets the gearbox to allow the suspension arm to pivot around it spherical bearing. This example is a 2012 Sauber C31 rear wishbone mounting clevis, but is typical of several similar clevises in my collection of F1 parts, albeit they appear to get a little more sophisticated in shape each year.
As F1 shifted from push rod rear suspension to pull rod, the packaging of the various compliant elements pivoting on it became more complex too. Here we can analyse in depth the lower section of a Sauber C30-C31 rear pull rod rocker from 2011-2012. This part pivots in a subframe mounted inside the gearbox, to operate the side springs\dampers, heave spring\dampers and anti roll bar.
With the shift toward pull rod rear suspension, the teams’ mechanics are faced with a maintenance issue. As the pull rod reaches down into the gearbox casing, access to the transmission is hindered by the inboard suspension inside the gear casing. Most teams maintain their transmission by first having to remove parts of the inboard suspension. However the Ferrari engined teams have each found a neater solution to this problem. Sauber use the Ferrari gearbox and also follow a similar practice of using a separate module to mount the entire inboard suspension in between the engine and gearbox.
Sauber have been a leader in aerodynamics this year, with the C30 gaining many compliments from other F1 engineers. With revisions to their front wing this weekend In Japan, it seems good time to delve a little deeper into the complex design of the wing. Their current wing dates back to the Spanish GP and has several features unlike any other on the grid. In Japan the wing gained a new winglet added to the cascades and a small change to the main endplate/
Its been announced today that the FIA have issued a Technical Directive clarifying the issue that emerged over the Monaco weekend around the Red Bull floor hole. This TD-13 outlines that the area 650mm outboard of the cars centreline cannot now exploit fully enclosed holes. As a result Red Bull will have to change the floor design before the next race, the Canadian GP. Although their design has now been deemed to be illegal retrospectively, so they are allowed to keep their results from the three races in which the design has been raced, including the win in Monaco.
Having introduced a “tyre squirt” slot into the floor ahead of the rear tyres at the Bahrain GP, Red Bull had completed two complete GPs before rival teams raised questions about its legality. On the morning of the Monaco GP, several teams started a discussion regarding the slots legality, as it did not follow the practice of Sauber or Ferrari in linking the hole to the edge of the floor. No formal protest was made, but the Technical Working Group (TWG) wanted the rules around holes in the floor clarified.
Sauber have proven to be one of the more progressive teams with aero development this year. The team’s have played with several different approaches to aero and exhaust positioning over the opening months of the year.
Now Sauber have produced their fourth sidepod iteration and surprisingly it is a McLaren style exhaust outlet. This goes away from the path they forged with the ramped downwash sidepod. Aiding the new exhaust position is a revised vane over the top of the sidepod.
The team also ran a revised front wing. I will cover this development in a separate post.
Sauber launched their car with a simple sidepod (above); this almost looked like a Red Bull RB5 set up, with the top exit exhaust aimed generally over the rear bodywork. This simple initial attempt was probably just for the launch pictures.
As soon after, the definitive Melbourne spec exhaust was tested. This sported a distinctive ramped section, which created a downwash that drove the top exit exiting exhaust flow downwards, then the ramped tail of the diffuser encouraged the flow to follow the sidepods line down towards the rear tyrediffuser. This mix of downwash and coanda effect all but reproduced the EBD effect used in 2011. As the exhaust flow was directed along the bodywork, it appears to be more accurate way of directing exhaust flow towards the diffuser. However the effect lacks a path for the sidepods undercut airflow to pass through. Red Bulls Melbourne spec (V2.0) exhaust attempted to cure this with the cross over tunnel.
To aid the downwash flow over the sidepod Sauber added a horizontal vane over the front section of sidepod. This front 15cm of sidepod is free of the bodywork restrictions of the main sidepod volume. The vane points the airflow downwards, to drive greater flow over the exhaust exit. In isolation this vane actually creates lift, as is common with F1 aero this counter intuitive solution creates more global downforce because of its downstream effect, than the small loss in downforce its creates on its own.
In practice for subsequent races Sauber tried a third iteration of the exhaust, still with a top exit, but the exhaust faired-in and blow out through scalloped slot, presumably to better direct the airflow. Using similar interpretations of the exhaustbodywork rules as McLaren exploited with their side exiting exhaust. This V3 set up wasn’t raced and will probably never race, with this fourth version now seen in testing.
The V4 sidepod discards the philosophy of the firth three completely, instead the sidepod is shorter and the coke bottle area forms a much tighter waist. Protruding from the flank of the sidepod the exhaust sits inside a small bulged fairing. This fairing mimics the McLaren with the open topped channel cut in to it, to allow the downwash to redirect the exhaust flow. The channel probably also provides a small degree of coanda effect in bending the exhaust flow downwards, but far less than with the earlier sidepod designs.
Exhaust flow exiting the duct now passes openly towards the tyrediffuser intersection. With the coke bottle area now free of the ramped section, the undercut sidepod flow can pass towards the centre of the diffuser to use the energy in the flow to drive some downforce from the trailing edge gurney and starter motor slot.
With the change in sidepod profile and the exhaust exiting more sideways the through the top, the downwash vane has also been altered. Rather than a horizontal vane, the vanes curved around the frontal of the sidepod, to create the depression over the revised exhaust outlet position.
Car: Sauber – Ferrari C31
On first sight the Sauber appears to be a well developed conventional package. Indeed in most areas the Sauber appears unremarkable, but this belies the wealth of small details around the car. In particular the cars aerodynamics make it quite progressive in comparison to its midfield rivals.
Also setting Sauber apart from almost every other team is its technical Structure. After the team had transitioned from BMW back to Sauber, long time technical director Willi Rampf retired and James key joined the team from Force India. However Key departed the team on the eve of the cars launch this year and its Sauber’s intention to continue without this central role. Instead the Heads of Department will work together to manage the technical side of the team. The two key people involved in this are Chief Designer Matt Morris and Head of Aero Willem Toet. This is certainly a unique arrangement, while I can imagine this working short term as the people involved are so experienced. They will be able to manage tactical decisions, but part of the technical directors role is set out the strategy and plan for the team in the years ahead. This is harder as the budget and resources need to be apportioned centrally to each department. Hopefully the team will resolve the management structure before they lose direction.
Sauber’s interpretation of the 2012 nose is unique; the team have followed the low nose and high chassis route, but like Red Bull have sought to offset the problems of keeping the airflow attached over the step in the nose. The removable nose cone has a rectangular cross section, while the front bulkhead has a slight “V” section. Where these two sections meet there is a corresponding gap behind the nose cone formed by the concave surface on the top of the chassis.
Many observers immediately likened this to the Ferrari 2008 nose hole, but such a solution would be illegal with the post 2009 nose rules, that demand the ‘nose’ is an open section, not to mention the neutral centre front wing section would not make much use of such a nose hole.
I believe the step is a rear facing blown slot, to help the airflow attach to the flat chassis top. Inside the nose cone, there is a duct that takes high pressure from a slot underneath the nose and passes it up to the rear facing slot.
This creates a shear layer between the flow over the nose and that formed above the chassis. With this set up, the nose and chassis can be nearer horizontal and squarer in section, without the issue of flow separation; this allows the maximum amount of space beneath the raised chassis for airflow to reach the turning vanes and the underfloors lower leading edge.
In doing this Sauber have been very clever with their reading of the rules. The nose must be formed of an open section, and then the only openings in that are for the driver cooling hole, which must be for the primary purpose of cooling the driver. Sauber’s nose cone can be considered an open section; as the lower inlet slot and the upper outlet slot are both formed in the plane between the nose and chassis, thus the nose has no extra holes and is legal.
Curiously the normal driver cooling hole has not been present on the car during testing.
The nose cone itself follows Sauber 2011 pattern in that the nose is very long and features a high and wide nose tip. Flow spilling of the noses top surface is controlled by a small fin running horizontally along the nose. This aligns with the front upper wishbone. With the noses upper surface being flat, the underside slopes down quite steeply aft of the front wing mounting pylons. This set up collects a lot of air beneath the nose tip and directs it towards the under nose vane set up. These are pair of curved vanes, each split into two sections, mounted below the front suspension. Coincidentally a design path Red Bull followed in the middle of last year
Aside from the need to meet the doubling of the wing deflection test, the front wing appears to be based around the late 2011 spec front wing. Sauber 2011 front wing
Although it may not appear so at first glance, the Sauber roll hoop is heavily undercut. The inlet snorkel is flanked by four supports; these are part of the metal inner roll hoop structure. The snorkel does not merge with the chassis until the rear pair of these supports, making over half of the roll structures length undercut. This aids airflow over the top body and to the rear wing.
Traditionally Sauber have gone for quite extreme shaped sidepods, this year the undercut does not appear as large, as the inlets are now much smaller. The “P” shaped inlets being very small and mounted inboard, leaving a large between them and the sidepod vanes. The sidepods then sweep in and downwards, with their lower edges tapering out towards the floor. As is common this year cooling is managed by the radiators directing their outflow towards the cars centre and then around the aerodynamically shaped heat shields around the engine, to exit out the back of the engine cover. In Sauber’s case, there are two main exit areas. Firstly pair of tall vents at the tail of the sidepod and then a tail funnel. Although this is not a Red Bull style oval tail funnel, but instead a pair of vertical slots in the rear most section of the engine cover. Albeit an oversized Red Bull style funnel was tried in testing, presumably for the upcoming hot weather races.
The launch specification sidepod was soon replaced with a design aimed at a more beneficial use of the exhaust gasses. The sidepods sported a top surface that sweeps down over the exhaust outlets and merges with the floor.
This creates a downwash effect over the exhaust outlets and the merging of the exhaust outlet to the sidepod surface induces a coanda effect to make the exhaust flow downwards, despite the upward angle of the exhaust outlet.
This exhaust flow is aimed at the floor between the rear wheels and the diffuser, to achieve the same but less powerful effect of the 2011 blown diffuser.
To aid the downwash effect created by the sidepods shape, the team have added a new vane, placed laterally across the sidepod. This turns the airflows downwards to increase the pressure over the exhaust jet, which will help it to be redirected towards the floor.
This vane is similar to the pod wings that first appeared on the Jordan cars on Hungary 2004. Under the post 2009 aero rules this bodywork is legal because it sits 450mm forward of the rear of the cockpit template. Bodywork this far forward is exempt from the same restrictions the main sidepods must conform to.
Sauber use the Ferrari gearbox, but their aerodynamic packaging of the bodywork around the gearbox, make the gear case is more visible. It’s possible to see how Ferrari have followed Williams practice to lower the top of the case to a point below the top wishbone mounting. This wishbone mounts to pylons projecting up from the gear case. This repackaging was partly possible through the repositioning of the springsdampers to low down on the gearbox with the use of pull rod activation. The rear of the upper wishbone mountings also forms a mounting for the beam wing; this large structure emerges from the gearbox and hooks around to mount the top of the beam wing. This looks like a duct, but it’s hard to see how flow could be effectively ducted to the top of the gearbox and then out of the beam wing. Although the rules do have a loophole that allows a small 15cm slot in the middle of the wing, which might help the airflow up out of the centre of the diffuser. But, in my opinion this isn’t a duct, as there’s no evidence of the outlet in the beam wing.
Diffuserrear impact structure
As seems to be the trend this year, the rear impact structure curves in between the diffuser and beam wing, this allows a clear flow of air to both devices. In Sauber’s case the impact structure is very slim, although the tail lamp section has add-on bodywork to make it much larger and rounder than the rest of the structure.
The diffuser is a straightforward interpretation of the rules. The boat tail section of diffuser is exposed below the crash structure; this allows the downwash airflow over the sidepods to enter the specially shaped starter motor hole and also to pass upwards over the large curved flap in the centre of the diffuser. Either side of this flap, the trailing edge of the diffuser, between the rear wing mounts, sports a smaller aerofoil section flap. All of these trailing edge devices help to reduce pressure behind the diffuser, this helps draw more flow through the diffuser for more downforce. Unlike last year the current rear wing endplates do not extend behind the diffuser to form vanes effectively extending the diffuser lengthwise.
In order to package the very narrow sidepod fronts the car sports a single Side impact spar mounted in the upper front volume of the sidepod. Typically teams use two spars here, one smaller leading spar and a larger spar trailing that. Impressively Sauber seem to be able to get the crash protection and the aerodynamics shape from a single stout spar.
Having used a unique hollow spoke wheel from OZ for several seasons, this year’s wheels are a revised version, going from five spokes to seven and the wheel incorporate fixings for the rim fairings.
Sauber continue to use the Ferrari powertrain, this consists of the Engine, KERS and gearbox.
A small introduction to Sriram Chandra:
Sriram contacted me with pictures and information, he’d independantly gathered at the Barcelona test. Amongst these was the first explanation of how the Sauber nose duct works.
Sriram is from India, where he completed his undergraduate degree in Electronics, but he realized he really wanted to specialize in Aerodynamics and especially F1. So he has moved to Europe and has since completed a Master’s degree in Aerospace engineering from ENSAE, Toulouse, France. He did his final internship in the Future Projects Office designing aerodynamic and fuel efficient aircraft.
Until he finds a break in F1, he is working in Toulouse for Altran, focusing on the Handling qualities of the A320 aircraft.
Sauber produced a major upgrade for Suzuka, which comprised of “new front wing, new rear wing, new turning vanes and side pod deflectors, new brake ducts and modifications to the floor”. Most visually different was the front wing which is covered in detail here. But the other upgrades were just as important. The rear wings frontal profile forms a slight “M” shape, with the leading edge being slightly lower at its outer and central points. The sidepods have been revised with a new cooling exit panel and the exhaust tucking back into the coke bottle exit, thus no longer in a Red Bull “outer blown” style.
In detail the front wing sports a new profile and revised endplates. The leading edge forms a fairly flat profile and then lifts into an arc to meet the endplate. In a similar way that Red Bulls wing meets the FIA central section at 90-degrees. As such it aims to achieve the same function to create a strong vortex, in Saubers case to carry airflow out around the front tyre.
The wing is formed of three main elements, the main plane being very short with much longer chord flaps behind it. As is common for most teams now, the flap adjusts cross about 75% of the span. The outer 25% section being at a fixed angle of attack, as it forms part of the endplate. Along the intersection between fixed and adjustable sections of flap, Sauber fit the pod for adjusting the front flap angle (FFA), used during pitstops.
Atop the endplate is the revised vane and cascade arrangement. The vane is now more rectangular in appearance and serves both to direct airflow and meet the minimum side-elevation bodywork surface area for the endplate. To this are fitted two cascade elements, a larger two element winglet and the smaller single element winglet. These downforce producing sections also are angles to aid the general outswept airflow in this area.
Now simply known as Sauber Motorsport the Team are embarking on their second as a born-again independent. Their new car, the C30 has been completed under the technical leadership of Ex-Force India TD James Key. James bring his experience from the budget conscious FIF1 team and its forebears JordanMidlandSpyker. Aiding key are two Long term Sauber staff, as Christoph Zimmerman as Chief Designer and Seamus Mullarkey leading the aero dept.
Development was held back last year as the team focussed its resources on the new car, which first hit the wing tunnel in May. This switch in resource was partly the reason the exhaust blown diffuser was not developed in 2010. Their new car sports just such a device, with an interesting twist. Otherwise the car is largely a logical evolution of the already quite advance concept of the C29. With Key having sorted the Ferrari engine installation problems and the cars ride height sensitivity which blighted the teams early season last year, Now the team can expect a strong run in the midfield for 2011.
Sauber went the right direction with the front of the chassis last year. So this C30 doesn’t look too different in this regard. The front end is slightly higher, with eh slight “V” section, while the nose cone is slightly wider. Current the turning vanes and front wing are carried over from the C29, so we can expect Sauber to also adopt some more typical concepts for these parts, especially the turning vanes which currently differ to the conventional shaped vaned adopted by most teams. Also the philosophy of evolving the monocoque extends the roll structure, the roll hoop is now supported by four pylons, creating an exaggerated undercut for better airflow to the rear wing.
Either side of the tub, the sidepods now sport a slightly squarer profile, the inlets being “U” shaped rather than triangular as they were last year. Yet this bulkier shape still allows for a huge undercut, leading back to a slimmed coke bottle shape, which now ends with a vertical slit to allow cooling air to escape early, and also allowed the exhaust to exit close the floor and the cars centreline. Also aiding cooling is the enlarged exit above the gearbox. While the top body exhibits no form of shark fin. Routing hot air out through here, keeps the tail of the coke bottle shape slim, for greater airflow over the diffuser.
In fact the diffuser is not quite as simple as the first pictures suggest and during the unveiling the diffuser was covered with a tarpaulin. However, I was able to look down onto the top of the diffuser. Sauber have kept the gearbox and sidepods so narrow that they have created a channel between the outer tunnels, which the exhaust blows through. This would work the centre section of diffuser, which is typical struggling for airflow, by the lower ride height of the step beneath the car.
Above this the on-trend exposed beam wing has been created by shaping the crash structure within the rules to bend underneath the wing. Currently the beam wing is a simple straight slot-less affair. This could be made work harder in conjunction with the blown diffuser, by adding a longer section in the middle 15cm of the wing.
Another rear wing aid to the diffuser is the addition of a series of vanes hanging below the endplates. These sit within a legal loophole in the rules, and effectively make the diffuser longer than the rules envisaged.
The upper rear wing, is adjustable and this system is known with the technical F1 staff as the ‘Drag Reduction System’ DCS. Saubers is a elegant solution to making the flap hinge about its trailing edge. A simple metal lever moves to open the slot gap up, reducing drag and boosting top speed.
Mechanically the car retains the Ferrari drive train. So again the car will sport the Ferrari gearbox, which is a hybrid Titanium and Carbon fibre construction. Therefore Sauber will adopt Ferrari KERS and their inboard rear suspension geometry. Technical Director James Keys explained the pushrod mountings, place the hardware at the very front of the gearbox, this keeps the parts accessible, but does not affect rear aerodynamic volume. Key also confirmed Sauber have designed and built the suspension that attaches to the Ferrari gear case, while the Hydraulics and Electronics are all Sauber designed too.